Selective Ring Opening of Methylcyclopentane and Methylcyclohexane Over Iridium Bifunctional Catalysts Supported on Surf
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Selective Ring Opening of Methylcyclopentane and Methylcyclohexane Over Iridium Bifunctional Catalysts Supported on Surface Modified c-Al2O3, SiO2 and Ultra Stable Y Zeolites R. Nageswara Rao • Nansuk You • Songhun Yoon Dipali Pravin Upare • Yong-Ki Park • Chul Wee Lee
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Received: 23 December 2010 / Accepted: 24 February 2011 / Published online: 11 March 2011 Ó Springer Science+Business Media, LLC 2011
Abstract Selective ring opening of methylcyclopentane (MCP) and methylcyclohexane (MCH) over a series of Iridium catalysts supported on c-alumina, silica and ultrastable Y (USY) zeolites was investigated. The acid density of the supports was modified by co impregnation of potassium in small quantities and its effect on conversion, yield and selectivity was evaluated. USY zeolites showed 26.9–38.1 and 27.5–33.7% of conversion with ring opening selectivities between 56.4–63.8 and 94.3–97.7% for MCP and MCH, respectively. Whereas on silica, the conversions were 10.7–16.6 and 10.4–14.0% with 96.9–99.0 and 93.3–99.1% selectivity. Interestingly, potassium acted as a promoter in case of USY zeolites while suppressed of activity of Ir supported on c-alumina and silica. The reaction conditions such as temperature, pressure, contact time and the feed/catalyst ratio were optimized. The evaluation of catalysts’ activity and selectivity towards ring opening of MCP and MCH is of great importance in understanding which catalyst modification could be effective in treatment of gasoline/diesel feed stocks for improving octane/cetane rating and fuel quality.
N. You S. Yoon D. P. Upare Y.-K. Park C. W. Lee (&) Green Chemistry Division, Petroleum Displacement Technology Center, Korea Research Institute of Chemical Technology, Daejeon 305-600, Korea e-mail: [email protected] R. Nageswara Rao Analytical Chemistry Division, IICT, Tarnaka, Hyderabad 500007, India D. P. Upare School of Science, University of Science and Technology (UST), Daejeon 305-333, Korea
Keywords Ring opening Hydrogenolysis Bifunctional catalyst Selectivity Fuel quality
1 Introduction Selective ring opening of naphthenes is one of the most viable processes to produce transportation fuels with high octane/cetane numbers from bitumen derived crude and heavy oils [1, 2]. It is a very complex reaction and represents a challenge in catalyst development. In general, the hydrogenolysis of C–C bonds is accompanied by a number of reactions viz., dehydrogenation, isomerization, cyclization, aromatization and cracking [3–5]. It involves bifunctional catalysts containing both metal and acid sites working together at high pressure and temperatures in the presence of hydrogen [6]. The acidic sites catalyze dehydrogenation, cracking, isomerization and dealkylation while the metal sites promote hydrogenation, hydrogenolysis and isomerization. Selective ring opening is generally carried out on certain noble metals and their hydrogenolysis ability increase in the order of Pt \ Pd \ Ru \ Rh \ Ir supported on Al2O3, SiO2, and zeolites [7–9]. Owing to its intrinsically
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